Method of joining plastic pipe

ABSTRACT

This invention relates to a method and device with which two ends of a plastic pipe may be joined. More particularly, the invention includes insert members with flanges on one end, clips which clip onto the flanges thereby retaining the inserts in abutting relation, a resilient deformable sleeve or coupling member having external serrations and which bridges the ends of the pipe being joined and lastly means to transfer the external serrations on the coupling to the inside of the pipe where such interlock with serrations on the insert member.

United States Patent 1 1 Demler, Sr.

1 Sept. 30, 1975 i 1 METHOD OF JOINING PLASTIC PIPE [75] Inventor: Henry William Demler, Sr..

Lebanon, Pa.

Assignee: AMP Incorporated, Harrisburg, Pa.

Filed: Nov. 11. 1974 [2!] Appl. No.: 522,652

Related U.S. Application Data [62] Division of Ser. No. 351.742. April 16. 1973. Pat.

52] U.S. Cl 29/450; 29/525 1] Int. Cl. B231 11/02 58] Field of Search 29/525. 450. 235. 237. 29/432; 285/371, 382, 382.1, 382.2, 382.7, 285/398 [56] References Cited UNITED STATES PATENTS 3.149.860 9/1964 Hallesy 285/382 X 3.378.282 9/1968 Demler 285/382 X 3.474.519 10/1969 Hallesy 29/432 3.674.292 7/1972 Demler 285/382 X 3.740.832 6/1973 Toepper 29/525 X 3.762.059 10/1973 Dawson 285/3822 X 3.765.708 10/1973 Pease i 285/3822 3.777.354 12/1973 Masters 9/ 37 Primary E\'u/ninerCharlie T. Moon Atlornqv. Age/21. or Firm-Allan B. Osborne. Esq.

[57 ABSTRACT This invention relates to a method and device with which two ends of a plastic pipe may be joined. More particularly. the invention includes insert members with flanges on one end. clips which clip onto the flanges thereby retaining the inserts in abutting relation. a resilient deformable sleeve or coupling member having external serrations and which bridges the ends of the pipe being joined and lastly means to transfer the external serrations on the coupling to the inside of the pipe where such interlock with serrations on the insert member.

1 Claim. 4 Drawing Figures U.S. Patent Sept. 30,1975 Sheet 1 of2 3,908,261

US. Patent Sept. 30,1975 Sheet 2 of2 3,908,261

METHOD OF JOINING PLASTIC PIPE This is a division of application Ser. No. 351,742, filed Apr. I6, 1973, now U.S. Pat. No. 3,877,735.

BACKGROUND OF THE INVENTION Buried plastic pipe is often accidently severed by earth digging equipment. Further, it is often intentionally severed by utility crews to provide access to lowerlying pipe or to lay pipe at a greater depth than the plastic pipe. Whatever the reason for such severance, the plastic pipe requires repairing and generally as soon as possible. As is well known'to those experienced inthis field, buried pipe cannot be readily moved longitudinally if at all. Provided some earth on one or both sides of the pipe is removed some limited lateral movement is possible.

The present method of repairing buried plastic pipe requires that several feet of pipe be cut out and a flanged fitting fixed to each end by fusion or solvent welding or by use of a mechanical fitting having inserts. A section of steel pipe having a corresponding flanged fitting on each end is dropped into place between the ends of the plastic pipe and the fittings bolted together. In most cases there must be some longitudinal movement of the plastic pipe to adjust for errors in cutting, different size flanges and the like. Further, the present method requires considerable excavation and in most soils cathodic protection for the metal flanges, inserts and the replacement pipe section. Obviously this method is time consuming and requires skilled workmen to effect a repair.

Accordingly, the present invention provides a coupling device useful for joining the ends of two plastic pipes which comprises a pair of rigid inserts for sliding into the end of the pipes; these inserts being tubular and having a flange on one end and serrations along the tubular section; a pair of half-moon clips which are adapted to be slipped over the flanges when they are in abutting engagement to secure them together, an elongated couplingmember having serrations thereon and which is adapted to be slid over the clip-held flanges and which extends along the pipe in both directions therefrom, and a pair of rigid rings which are forced over each end of the coupling member and by so doing secure the coupling member to the enclosed length of pipes by means of reforming the serrations from the coupling member to the inside of the plasticpipe and into interlocking engagement with the serrations on the inserts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded, partially sectional, perspective view of the present invention;

FIG. 2 is a cross-section view of FIG. 1 after the union has been completed;

FIG. 3 shows a collar useful in the present invention; and

FIG. 4 shows a completed union of FIG. 2 utilizing the collar of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT The coupling device constructed in accordance with the present invention consists of a pair of tubular insert members, a pair of half-moon retaining clips, one deformable coupling member and a pair of rigid rings. As each of the elements constituting a pair are identical one to the other, one reference numeral assigned to each feature on one element will apply to the same feature on the other element; to distinguish one element from the other, the reference numerals on one will include a prime mark.

Referring now to FIG. 1, specific features of each of the elements will be pointed out.

The tubular insert members 10 have an unencumbered lead-in end 12 and a flanged abutting end 14. The annular flange 16 projects outwardly a predetermined distance. Intermediate the two ends is a serrated section 18 such section consisting of a plurality of individual serrations. Insert members 10 must be reasonably rigid under applied external forces and for this reason, the diameter of passageway 20 therein may be maximumized but only to the extent consistent with this limitation. The outer diameter of the inserts are predetermined so that they fit snugly into the ends of the pipes being joined.

The half-moon or semi-circular retaining clips 22 have a predetermined thickness and width. While the outside surfaces of the clips are preferably smooth the inside surfaces contain grooves 24. The preferred depth of these grooves are substantially equal to the distance flanges 16 project. Both tubular inserts l0 and retaining clips 22 are preferably made from a nondeformable material such as steel.

The only single; i.e., non paired element, in the present invention is coupling member 26. However, it is not without symmetry as one half thereof is the mirror image of the other. A center section 28, defined by two spaced apart annular ribs 30, bisect the member. On each end 32 there is an annular retaining rim 34. This rim, which projects outwardly, is beveled on the side facing away from the center section 28. The side facing the center section is perpendicular to the longitudinal axis of the member. Intermediate rib 30 and rim 34 on each half are two serrations 36, which, like rims 34 have one beveled side and one perpendicular side. As seen in FIG. 1, the tops of serrations may be flat and preferably should be of some width. The position of the serrations on coupling member 26 must be in or close to alignment with serrations 18 on inserts 10 when the coupling device is assembled. The purpose of beveling one side is simply to facilitate assembly of the coupling device and is not critical per se to the invention. The passageway 38 defined by coupling member 26 is larger than the outer diameter of the retaining clips 22 when clipped onto flanges 16 but only to the extent necessary to allow the member to slide over the clips. Coupling member 26 is made from deformable plastic and preferably has some transparency.

The rigid rings 40 consist of a tubular section 42 which is terminated at one end by outwardly projecting flange 44. The distance that the flanges project is preferably substantially equal to the distance ribs 30 project. Passageways 46 in rings 40 have smooth walls and a diameter that is undersized with respect to the outer diameter of coupling member 26 as measured at rims 34-serrations 36. Rings 40 may be made from steel or other non-deformable material.

Pipes 50, seen positioned in passageway 46 in rigid rings 40 in FIG. 1 are of plastic or other deformable material. The only preparation of such pipe required is that the ends 52 be squared off.

UTILIZATION OF THE PREFERRED EMBODIMENT FIG. 1 shows in exploded fashion the elements of the coupling device constructed in accordance with the present invention. As is apparent, the elements have been exploded in the manner in which the device is assembled. FIG. 3 to which reference is now made shows in cross-section the assembled coupling device securely holding pipes 50-50 together.

The first step is to laterally move each pipe 50 so that ends 52 are displaced one from the other and are unobstructed by the other. Then rigid rings 40-40 are slid onto pipes 50-50. The next step is to slide coupling member 26 onto either pipe 50 or 50. While the above step can be deferred, it is more logical to group like steps so as to simplify assembly.

Inserts -10 are now inserted into open ends 52-52 of pipes 50-52 at least far enough so that the pipes cover serrations 18-18.

With the tubular inserts in the pipes, the pipes are brought back into axial alignment so that flanges 16-16 abut each other. This may require longitudinal movement of the inserts but not of the pipes. Retaining clips 22-22 are then slipped on over the flanges; the flanges being received in grooves 24-24. As the diameter of the grooves are substantially equal to the diameter of the flanges, the clips hold the inserts together firmly. As noted above, the diameter of clips 22-22 is predetermined so that the outside diameter coincides with the outside diameter of pipes 50-50.

Coupling member 26 may now be slid over the aforementioned u'nion so that the mid point of center section 28 essentially overlies retaining clips 22-22'. If the member is transparent the positioning is obviously simplified. With the coupling member so positioned, serrations 36 thereon are in registration with serrations 18-18 on inserts 10-10.

The final step in the assembly of the coupling device is to force rigid rings 40-40 onto either half of coupling member 26 by means of a hand operated, plierlike tool which are found in most gas company repair trucks. As FIG. 3 shows, the rings are squeezed onto the member until flanges 44-44 abut ribs 30. As the diameter of passageways 46-46 is less than the diameter of serrations 36, these serrations flow inwardly. The deformation of the serrations is carried through the walls of pipes 50-50' so that the inside of the walls are extruded into interlocking relationship with serrations 18-18 on inserts 10-10. As the rings are squeezed beyond rims 34 the rims spring back to their original posi- Although two pipes may be securely and sealingly I joined together by the coupling device described above and illustrated in FIGS. 1 and 2, reinforcing of the joint may be provided by the addition of a reinforcing band shown in FIGS. 3 and 4. Band 80, which may be made from polyethylene, consists of a split collar 82 having a width slightly less than the width of center section 28 on coupling member 26. Collar 82 is placed around the assembled coupling device seen in FIG. 2 in the aforementioned center section 28 and radially squeezed until the hole in the single tab 84 is in registration with the holes in the double tabs 86. Pin 88 is slipped into the aligned holes locking the band onto the assembled coupling device in the manner shown in FIG. 4.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as some modifications will be obvious to those skilled in the art.

What is claimed is: 1. A method of joining two plastic pipes arranged end to end, said method comprising the steps of:

a. sliding a rigid ring onto each of said two plastic pipes; b. sliding a deformable cylindrical coupling member onto one of said pipes, said coupling member having serrations on the outer surface thereof and a smooth inner surface; c. providing a pair of tubular insert members, each having serrations on the outer surface thereof and a flange at one end, and inserting said members into the open ends of said plastic pipe with said flanges being in facing position one to the other; d. fastening said flanges together thereby joining said two plastic pipe; e. sliding said coupling member over said joined ends of said plastic pipe; and f. sliding each rigid ring onto an end of said coupling member whereby said serrations thereon are compressed and the structure thereof transferred to the inner walls of said plastic pipe in registration with said serrations on said insert members thereby locking said pipe onto said insert members. 

1. A method of joining two plastic pipes arranged end to end, said method comprising the steps of: a. sliDing a rigid ring onto each of said two plastic pipes; b. sliding a deformable cylindrical coupling member onto one of said pipes, said coupling member having serrations on the outer surface thereof and a smooth inner surface; c. providing a pair of tubular insert members, each having serrations on the outer surface thereof and a flange at one end, and inserting said members into the open ends of said plastic pipe with said flanges being in facing position one to the other; d. fastening said flanges together thereby joining said two plastic pipe; e. sliding said coupling member over said joined ends of said plastic pipe; and f. sliding each rigid ring onto an end of said coupling member whereby said serrations thereon are compressed and the structure thereof transferred to the inner walls of said plastic pipe in registration with said serrations on said insert members thereby locking said pipe onto said insert members. 